Answer:
a. Skype
Step-by-step explanation:
Based on the information provided within the question it can be said that the best communication method for Daniela's company would be Skype. This is a communication method that allows various parties to communicate through video chat as well as instant messaging and is available in a wide range of platforms, making it's availability extremely high. The other options available will not allow the employees to see each other when they communicate.